Presently, it is being discussed and proposed to introduce a very small base station targeted for certain users for implementing FMC (Fixed and Mobile Convergence) services (see “Requirements for LTE Home eNodeBs”, RP-070209, 3GPP TSG RAN #35, Lemesos, Cyprus, 6-9 Mar. 2007). In LTE (Long Term Evolution), whose specification development is being currently ongoing, as a successor to the third generation radio access scheme, such very small base stations targeted for certain or specified users are collectively referred to as Home eNBs (or Home e-NodeBs). The Home eNB is a so-called plug-and-play type of apparatus that a user can buy and install at a desired location without the necessity of operator's manual installation, maintenance and management.
The Home eNB may have overlapped geographical areas with public targeted base stations (which are conveniently referred to as “macro eNBs”) that are constituents of an existing public communication network. Also, its serving frequency is enabled in combination with frequencies served by adjacent macro eNBs. As a result, when a mobile station migrates from an area covered by an adjacent macro eNB (referred to as a “macro cell”) into a serving area of the Home eNB, efficient cell search and/or handover may be required.
In a conventional mobile communication network, abase station uses common control channels such as BCHs to broadcast center frequencies used by adjacent base stations for fast inter-frequency cell search and fast inter-frequency handover at a mobile station. Before placing a new base station into service, an operator investigates the center frequencies used by adjacent base stations serving other coverage areas bordering a coverage area served by that new base station and then generates an adjacent cell list, which is installed in the new base station. A mobile station could receive a common channel such as a BCH broadcast from a base station providing a resident cell and determine the center frequencies used in other cells adjacent to that cell. Among many possible center frequencies, the mobile station could identify the center frequencies presently used in the adjacent cells, which results in faster cell search and handover at cell transition. As a result, the mobile station can select optimal cells while maintaining communication quality of dedicated links.